Featuring two short videos and four photographs of a 6-series based prototype, the website provides no additional written information about the prototype other than suggesting the car in question is “more than a 6-series” and “not in its final stage”.

Close inspection reveals the matt black BMW mule features a new front end resembling that of the one-off EfficientDynamics concept revealed at last year’s Frankfurt motor show.

Insiders at BMW’s headquarters in Munich have confirmed to Autocar that plans to create a prototype featuring a similar driveline to that showcased in the EfficientDynamics concept have been progressing for some time. “We’ve revealed our vision. Now we want to put it into practice,” said one source.

However, they stop short of confirming the 6-series-based prototype featured in the German car maker’s latest viral marketing initiative is that car.

The video footage of the new BMW reveals it to be at least partly electrically powered, with no obvious engine noise as it accelerates away from standstill. A single tailpipe at the rear also suggests it houses a conventional engine as part of a petrol-electric driveline layout.

The four-wheel drive EfficientDynamics concept uses two electric motors – one acting on the front axle with 60kW, the other housed in a six-speed double clutch transmission with 38kW. The electric motors are powered by energy stored in a battery pack consisting of 98 individual cells that are charged in part by a 1.5-litre three-cylinder engine with 120kW.

Join the debate

I'll tell you something, if BMW do it, they'll do it correctly, and along with Porsche and their take on this hybrid system, a lot of the other car makers are going to look pretty silly, a lot of red faces, we all want performance at various levels, but just think,supercar performance without the guilt?,and good mpg, motoring nirvana, don't you think?, so before you all start, give them a chance, ok?.